I have a One seven and when i get one it it runs, but then it doesn't shift into second gear. It goes into neutral and just revs and rolls to a stop. I have taken the gear box apart and can not find anything broken and everything looks right. Once the rpms come down, the car shifts back into first.

I have posted this on a few other sites and people say to check the second gear bearing.

I don't know if something is slipping or could be bad and look normal. Any thoughts?

Reverse is not being used and the arm for gear box is pulled and held forward. Does this move at all when the car shifts into second?

Check the 2-speed assy. Make sure the the arm portion is free and not binding.
Also make sure the 2nd gear drum does have the pin in it (circled in yellow) if the pin is missing 2nd gear will not engage. The one-way bearing is on the 1st gear assy. It is designed to be engaged when the model takes off and is in 1st. gear. The bearing freewheels when 2nd gear is engaged.

Yes the pin in in the drum for the 2nd gear. The other day when I was working on it I was able to get I to shift into second, so I put it back together and now it won't. First gear works fine, but scone just doesn't wan to engage. A few months back I had taken it apart and Put it back together and it worked for about 2 tanks then would sometimes work, then just won't. I think somethin is loose or worn out but I can't find it